The present invention, in some embodiments thereof, relates to a support for a conduit in a body of a person or an animal, and in particular to a support for a grafted vessel inside a body.
Coronary Heart Disease (CHD) is considered one of the leading causes of death in both men and women. The disease pathophysiology involves a buildup of cholesterol plaque in a blood vessel to a point where the vessel may be partially, or wholly, occluded.
Two known techniques for treating occluded coronary vessels are Percutaneous Transluminal Coronary Angioplasty (PTCA) for opening the stenotic area with a balloon catheter, usually accompanied by placement of a stent to secure the opening; and Coronary Artery Bypass Graft (CABG) surgery for bypassing an occluded vessel with a graft implant. Several types of (autologous) coronary artery bypass grafts are known, such as internal thoracic grafts, radial and right gastroepiploic artery grafts, and saphenous vein grafts. These grafts generally originate from the aorta or its bifurcations or are constructed grafts. Synthetic grafts are generally considered alternative to autologous grafts, although their overall performance and patency is still investigated.
Blood flow through a grafted vessel may depend on multiple factors such as vessel length, diameter, shape, angles, flow patterns, etc. The graft position in relation to a target vessel (the vessel to which the graft connects at a distal end) has also an important impact on the flow. For normal blood flow through the bypass to the target vessel, the graft is generally required to be substantially patent, without stenosis or flow disturbances, such as turbulent flow.
U.S. Pat. No. 4,743,251 “VEIN PROSTHESIS AND METHOD FOR PRODUCING SAME”, relates to a prosthesis “intended to be implanted in a human patient for forming an aorto-coronary by-pass or another by-pass on other arteries. The prosthesis comprises a normal, unaltered living vein which is taken from the patient himself/herself and which is surrounded by a multiperforated flexible sheath. The inside diameter of the sheath is so chosen that, after implantation, the outside diameter of the vein is maintained by the sheath at a value less than the maximum possible diameter of the vein and that the inside diameter of the vein is suitable for the diameter of the receiver artery.”
U.S. Pat. No. 5,755,659 “METHOD OF MAKING A VASCULAR PROSTHESIS”, relates to “a vascular prosthesis for the replacement of blood vessels in the human or animal body, consisting of a section of a replacement blood vessel (3) which has been taken from a human or animal body and a fibro-elastic tube (2) which is drawn over this vascular section, whose intersecting threads (1) which form the tube wind in spiral form around the longitudinal axis of the tube, wherein the fibro-elastic tube (2) is extended pointwise in the longitudinal direction with alteration of the diameter or is compressed and thereby is caused to contact the replacement vessel evenly over its total area.”
US Patent Publication No. 2004/0215309 “COVERING ELEMENT FOR VEINS, METHOD FOR THE PRODUCTION AND USE THEREOF IN SURGERY”, relates to “sheathing for reinforcing natural veins for use as surgical implants in the form of textile netting that is configured by forming a seamless, tubular, essentially pile-less, knit fabric and has loops having large, open apertures having essentially polygonal shapes is made available.”
US patent Publication 2007/0293932 “COMPLIANT BLOOD VESSEL GRAFT”, relates to “stents and methods of using stents are provided. Stents of the invention provide external support structure for a blood vessel segment disposed within, wherein the stents are capable of resilient radial expansion in a manner mimicking the compliance properties of an artery. The stent may be formed of a knitted or braided mesh formed so as to provide the needed compliance properties. A venous graft with the stent and a vein segment disposed within is provided, wherein graft is capable of mimicking the compliance properties of an artery. Methods of selecting stents for downsizing and methods of using the stents of the invention in downsizing and smoothening are provided. Methods of replacing a section of an artery with a venous graft including a stent of the invention are provided. Methods of reducing intimal hyperplasia in implanted vein segment in a venous graft using stents of the invention are provided.”
U.S. Pat. No. 6,071,306, “EXTERNALLY STENTED VEIN SEGMENT AND ITS USE IN AN ARTERIOVENOUS BYPASS GRAFTING PROCEDURE”, relates to “an arteriovenous bypass grafting procedure in which a vein segment is implanted into the arterial circulation of a mammalian subject, wherein a non-restrictive porous stent is provided around the grafted vein.”